edu.uci.ics.jung.graph.DirectedOrderedSparseMultigraph.java Source code

Introduction

Here is the source code for edu.uci.ics.jung.graph.DirectedOrderedSparseMultigraph.java

Source

/*
 * Created on Oct 17, 2005
 *
 * Copyright (c) 2005, the JUNG Project and the Regents of the University 
 * of California
 * All rights reserved.
 *
 * This software is open-source under the BSD license; see either
 * "license.txt" or
 * http://jung.sourceforge.net/license.txt for a description.
 */
package edu.uci.ics.jung.graph;

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.Set;

import org.apache.commons.collections15.Factory;

import edu.uci.ics.jung.graph.util.Pair;

/**
 * An implementation of <code>DirectedGraph</code>, suitable for sparse graphs, 
 * that orders its vertex and edge collections
 * according to insertion time.
 */
@SuppressWarnings("serial")
public class DirectedOrderedSparseMultigraph<V, E> extends DirectedSparseMultigraph<V, E>
        implements DirectedGraph<V, E>, MultiGraph<V, E> {
    /**
     * Returns a {@code Factory} that creates an instance of this graph type.
     * @param <V> the vertex type for the graph factory
     * @param <E> the edge type for the graph factory
     */
    public static <V, E> Factory<DirectedGraph<V, E>> getFactory() {
        return new Factory<DirectedGraph<V, E>>() {
            public DirectedGraph<V, E> create() {
                return new DirectedOrderedSparseMultigraph<V, E>();
            }
        };
    }

    /**
     * Creates a new instance.
     */
    public DirectedOrderedSparseMultigraph() {
        vertices = new LinkedHashMap<V, Pair<Set<E>>>();
        edges = new LinkedHashMap<E, Pair<V>>();
    }

    @Override
    public boolean addVertex(V vertex) {
        if (vertex == null) {
            throw new IllegalArgumentException("vertex may not be null");
        }
        if (!containsVertex(vertex)) {
            vertices.put(vertex, new Pair<Set<E>>(new LinkedHashSet<E>(), new LinkedHashSet<E>()));
            return true;
        } else {
            return false;
        }
    }

    @Override
    public Collection<V> getPredecessors(V vertex) {
        if (!containsVertex(vertex))
            return null;
        Set<V> preds = new LinkedHashSet<V>();
        for (E edge : getIncoming_internal(vertex))
            preds.add(this.getSource(edge));

        return Collections.unmodifiableCollection(preds);
    }

    @Override
    public Collection<V> getSuccessors(V vertex) {
        if (!containsVertex(vertex))
            return null;
        Set<V> succs = new LinkedHashSet<V>();
        for (E edge : getOutgoing_internal(vertex))
            succs.add(this.getDest(edge));

        return Collections.unmodifiableCollection(succs);
    }

    @Override
    public Collection<V> getNeighbors(V vertex) {
        if (!containsVertex(vertex))
            return null;
        Collection<V> neighbors = new LinkedHashSet<V>();
        for (E edge : getIncoming_internal(vertex))
            neighbors.add(this.getSource(edge));
        for (E edge : getOutgoing_internal(vertex))
            neighbors.add(this.getDest(edge));
        return Collections.unmodifiableCollection(neighbors);
    }

    @Override
    public Collection<E> getIncidentEdges(V vertex) {
        if (!containsVertex(vertex))
            return null;
        Collection<E> incident = new LinkedHashSet<E>();
        incident.addAll(getIncoming_internal(vertex));
        incident.addAll(getOutgoing_internal(vertex));
        return incident;
    }

}